1. Field of the Invention
A closure device comprising at least one set of panels movable between an extended and a retracted position to selectively secure or close a portal such as a door or window when the set of panels are in the extended position.
2. Description of the Prior Art
Various security screens and grates are known in the art. These security devices are commonly heavy constructed such that opening or closing involves movement of a substantial weight. Often these devices are constructed of parallel linkages with angularly movable links that connect vertical bars in general traversing a plurality of such bars. Typical of such parallel linkage types is disclosed in U.S. Pat. No. 917,713. Other foldable structures use vertically movable bars. Such vertical movement may have unsecured areas above and below the screening. This type of device is shown in U.S. Pat. No. 1,721,998.
U.S. Pat. Nos. 4,006,768 and 2,754,902 show collapsible panels serving as security screens each having a roller attachment member disposed within a channel.
U.S. Pat. Nos. 1,581,854 and 931,421 disclose at least one set of hingedly attached panels permitting retraction by movement in the horizontal plane while the pair of hingedly attached members collapse onto each other. Further, it should be noted that U.S. Pat. No. 1,581,854 discloses a pair of wheels operatively disposed within a tract which is attached to the outer hingedly attached panel member.
Additional examples of the prior art are shown in U.S. Pat. Nos. 83,053, 145,773, 284,117, 560,937, 570,713, 958,481, 1,471,477, 1,501,545, 1,532,769, 1,715,208, 1,735,415, 1,750,989, 1,946,381, 1,989,392, 2,422,840 2,479,123, 2,687,170, 2,728,388, 2,754,902, 3,297,077, 3,670,797, 3,720,255, 3,743,001, and 3,942,576.